1968 Custom 16 motor height
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johnyrude200 |
Posted on 09/09/16 - 7:12 AM
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Hello All,
Just acquired an old Montauk and wanted to see what motor height people set there engines at. I have a 1993 70hp johnson powering this vessel. I can tell from experience that I think the motor is set too LOW. The stern bracket is resting on top of the transom with no gap.
When at WOT, the motor is creating a rooster tail (wrong), when I trim up a bit I can get rid of this, but than the boat starts to porpoise badly, even on glassy water. I can hit about 31MPH as it sits right now, and the hull does have some moisture in it (can't tell how much, was drilling holes to fill with 2 part resin to fasten down the console and seating, prior owner DID NOT do this, so of course water could enter the hull).
I am a mechanic by trade and have already used a measuring stick to line up the anti-ventilation plate with the keel. At full trim down with negative tuck nothing is lined up. With trimming up and both items in line, the boat porpoises. Even with plenty of ballast in the front this is still happening, so I surmise the motor is too LOW.
Just wondering if anyone else has run into this and found a 'sweet spot,' to help save me the effort of getting out the motor crane and going through the whole trial and error process, not to mention drilling additional holes in the transom and re-tapping the motor to accommodate the height change.
Thanks.
Edited by Joe Kriz on 09/13/16 - 1:53 PM |
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Phil T |
Posted on 09/09/16 - 8:44 AM
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Unfortunately your motor is mounted in the standard/original dealer position.
Research, trial and testing have shown the engine and boat will perform much better mounted 2 holes up. Refer to this article for reference.
http://www.whalercentral.com/articles...cle_id=106
Once remounted, retest and report back. We can then discuss the appropriate prop.
I would expect the boat could reach 36-38 mph once tweeked.
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johnyrude200 |
Posted on 09/09/16 - 9:28 AM
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Thanks for the advice, I'll remount and give it a try. I wanted to save some time by hearing what others have seen work best with this boat/motor combination, and hopefully avoid having to drill unnecessary holes in the transom. Looks like I'll be drill a few new holes to get this right! The prop is turning 5400-5500 RPM, the right numbers for this motor, but is only a 15 pitch.
Hopefully with the adjustment I might be able to gain a pitch or two...that would certainly help top end speed and economy. Motor is a gas-guzzler by todays standards (2-4MPG).
Edited by johnyrude200 on 09/09/16 - 9:33 AM |
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Joe Kriz |
Posted on 09/09/16 - 10:45 AM
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The Montauk was not made until 1973 so you must have an earlier model like a Nauset 16.
Let us know what model you actually have.
http://www.whalercentral.com/userphot...allery.php
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johnyrude200 |
Posted on 09/09/16 - 11:42 AM
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OK, looks like this is a Nauset/Eastport. Any updates on the recommendation for motor height? It is 16'7"...close enough to 17' for me!
Question - what is the difference between the hulls on the Nauset, Eastport, Sakonnet? From the pics, they all seem to look the same. I purchased this boat and none of the internals (seat/console) are period correct. I don't care about that, but I DO need to know how to optimize the motor performance along with the usual facts about the hull.
This is the first non-aluminum boat I've owned, so there is a learning curve here. Trying to do as much homework/research as possible.
Still a 'newb' to these forums, great resource for helpful info...thanks so much!
Edited by johnyrude200 on 09/09/16 - 11:48 AM |
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Joe Kriz |
Posted on 09/09/16 - 11:49 AM
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The basic difference between the Nauset 16 and the Eastport 16 is that the Eastport has the Stern Seat.
The console and pilot seat are the same.
Hope this helps you determine which model you have.
Now assuming your motor is mounted all the way down, you most likely need to drill new holes in your transom to raise the motor up.
See this article and let us know how your motor is mounted.
http://www.whalercentral.com/articles...icle_id=82
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Joe Kriz |
Posted on 09/09/16 - 11:52 AM
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The hulls are identical.
The only difference between the models is the interior.
If the interior is not period correct or aftermarket, then you have a "Custom" model.
http://www.whalercentral.com/faq.php?...p?cat_id=5
How sure are you that it is a 1968 year model?
Many times the Title is not correct.
See this info to find out what year you have if you know the Stencil number.
http://www.whalercentral.com/articles...icle_id=61
1968 ................. 37601 thru 39750
We are getting close to knowing exactly what you have.
1968 Custom 16 ?
Edited by Joe Kriz on 09/09/16 - 12:08 PM |
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johnyrude200 |
Posted on 09/09/16 - 12:18 PM
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There was no boat ID number. But, it does look just like the ones pictured from 1962-1973. I looked at all the models and my vessel is the same.
As a outboard mechanic (primarily Johnson/Evinrude 1945-2006), I call motors that have 5 different motors on them 'FRANKENMOTORS.'
This boat may fall under that category. The center console isn't period correct, and the seat is from a completely different manufacturer not original to the Whaler, but I'm happy with it.
Not looking to do a show room restoration, just a comfortable, presentable ride for regular boating.
Look forward to the feedback. Here are some pics, not done, still doing installations of stuff. Needs to be completely repainted and clear coated too. Last guy really cut a lot of corners.
johnyrude200 attached the following image:
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johnyrude200 |
Posted on 09/09/16 - 12:18 PM
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johnyrude200 |
Posted on 09/09/16 - 12:18 PM
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johnyrude200 |
Posted on 09/09/16 - 12:19 PM
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johnyrude200 |
Posted on 09/12/16 - 8:22 PM
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Following up. With the pics, is the recommendation to raise the motor by 2" based on experience and technical data? I was planning on 1", but dont want to compromise the transom by doing two adjustments if 1" isnt enough to stop the porpoising.
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Phil T |
Posted on 09/13/16 - 1:26 PM
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I would drill the green holes as shown in the article and mount the motor 2 holes up.
Note I am saying holes, not inches.
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johnyrude200 |
Posted on 09/13/16 - 6:16 PM
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Thank you Joe and Phil. I did not see the 2nd article Joe had posted about changing motor height. Here are the pics of the motor as it is mounted currently. What has me itching my head is that it is already at the #2 hole for the top bolts. The bottom ones are blind holes with the stern bracket tapped.
Is it possible the top bolt holes were moved at some point during this boat's life, and are set lower than originally tapped? The hull does appear to have had work done to it in the past. I'm guessing the transom may have been worked on too?
Using the articles as reference, I really only have a single hole adjustment of height on the top bolts; the bottom bolts, I haven't put a measuring tape yet, but I don't think they will reach the bottom 'slide' pattern bolt orifices of the stern bracket.
Has anyone had one of these 70hp OMC's mounted on one of their Newport boats similar to mine? Best placement recommendations?
johnyrude200 attached the following image:
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Edited by johnyrude200 on 09/13/16 - 6:19 PM |
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johnyrude200 |
Posted on 09/13/16 - 6:19 PM
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mtown |
Posted on 09/14/16 - 11:25 AM
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From what I see you could raise the motor 1 more hole up, but that would mean you would still have to drill
new lower holes as the "stud" mounts will no longer work. I angled slightly upward [ drilling from outside of stern] for my bottom bolts to enter the splash well high enough to accommodate a nut and washer.
I think Phil is right to drill the green holes. It will allow whatever height or motor you use. I have a 1964 and a 1966 with Yamaha on them. I spent a long time reading about raising the motor and thinking what a lot of trouble it would be. I did it on the 1964 and realized it was a lot easier than I thought. I did the 1966 the following winter. Very happy with the results.
I did both alone, used a Bobcat and rope with the second one. If you have an engine hoist it will be easy.
Just for reference, the 1966 [which I can measure] sits 1 5/8" inch above the transom.
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johnyrude200 |
Posted on 09/14/16 - 1:27 PM
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Well, comparing the length of the lower unit for a yamaha may be different than an OMC. Even comparing length for different HP OMC's reveals different drops!
Your 1 5/8" rise is helpful though. I measured the rise by raising the motor "2 holes," equates to 1.5," so that may be a coincidence but seems like it would help.
Probably raise the motor up in the next week so I can retest. Any recommendations for simple ways to fill in those old holes?
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Joe Kriz |
Posted on 09/14/16 - 1:44 PM
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It appears whoever drilled the upper holes did not use the BIA standard.
http://www.whalercentral.com/articles...icle_id=82
There is a standard pattern for drilling motor holes that all manufactures follow these days.
I suggest you look at the drawing again and you will see that the upper holes are drilled 1 7/8" from the top of the transom.
Yours appear to be around 3 1/2 inches down from the top. Not even close to standard.
There is NO difference between Yamaha, OMC, Honda, etc. They all use the Standard BIA mounting pattern.
Yes, the holes on the motor brackets are spaced 3/4" apart. Thus raising the motor 2 holes results in 1 1/2 inch raise.
All motors on a 16/17/ classic hull should be mounted 2 holes up. Some motors should even be mounted 3 holes up with the right prop.
You will need to drill the upper "Black" holes and the lower "Green" holes so you can mount your motor using a modified BIA standard.
The lower holes being modified in location.
The upper holes following the standard.
Use 1/2" diameter plywood plugs from 3/4" or 1" thick plywood and epoxy to fill the holes.
See this article we have in our Reference section.
http://www.whalercentral.com/articles...icle_id=62
Edited by Joe Kriz on 09/14/16 - 1:54 PM |
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mtown |
Posted on 09/14/16 - 1:48 PM
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To fill old holes it is probably easier to raise the bow than the stern. So, raise the bow as much as possible [the more the better].
Tape a piece of plastic trash bag, saran wrap ect. to outside of transom and whatever you want to protect splash well. Put an epoxy resin that has been mixed in a suitable container to squeeze it accurately in the splash well side of the hole. I use old saline bottles with the tip cut a little bigger. Fill the whole thing. Since you have not made the hull verticle, you will need to finish the splash well side with some thickened resin, or some other epoxy putty.
When you are drilling new holes it will give you a good read on any moisture in the plywood of the transom, if any.
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johnyrude200 |
Posted on 09/14/16 - 5:58 PM
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Thanks for confirming my suspicions Joe about the top drilled holes. Again, last guy really cut a lot of corners on this boat (as in, every aspect of it I'm finding). I'll make the adjustment as per everyone's recommendations.
I agree that the BIA standard for mounting holes are the same across brands. My point was that the lower unit for different motors isn't the same drop from stern bracket to ventilation plate, even within the same brand. For instance, a 1993 40/48/50hp OMC has about 22", whereas this 1993 60/65/70hp OMC has less drop.
The stern bracket pattern is the same, but the lower unit/exhaust housing isn't. So comparing the mounting height of the other guys yamaha to this OMC, it may randomly line up, but isn't necessarily right for the installation. That's why I was asking at the beginning specifically, have folks found a sweet spot for the 70hp OMC motors.
All good information though, thanks again for your help.
(please follow guideline #1 at the top of this page and use the full 4 digit year for everything)
Edited by Joe Kriz on 09/14/16 - 6:17 PM |
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